Numerical analysis on foam reaction injection molding of polyurethane, part B: Parametric study and real application

Abstract

Foam reaction injection molding (FRIM) is a widely used process for manufacturing polyurethane foam with complex shapes. The modified theoretical model for polyurethane foam forming reaction during FRIM process was established in our previous work. In this study, using the modified model, parametric study for FRIM process was performed in order to optimize experimental conditions of FRIM process such as initial temperature of mold, thickness of mold, and injection amount of polymerizing mixture. In addition, we applied the modified model to real application of refrigerator cabinet to determine optimal manufacturing conditions for polyurethane FRIM process.

A Review of Research on the Effect of Temperature on the Properties of Polyurethane Foams

“…Voids are created where the foam cannot be filled, and the polyurethane foams density decreases to varying degrees. Furthermore, studies by DaciaJackovich [ 44 ], Harbron [ 45 ], and Yeon [ 46 ] showed that increasing the mold temperature can effectively reduce the average density gradient, the density in the growth direction, and the uniformity of the cell (cells) of the foam. As the mold temperature increased, the average polyurethane foams cell size became larger, and the dimensional stability improved significantly.…”

“…Polyurethane foam materials are formed by the gradual polymerization of isocyanates, polyesters, polyethers, polyolefins, and isocyanate end groups of diols or diamine compounds and prepolyurethane foams [ 58 ]. The higher the temperature during the casting process, the higher the activity of the reaction material and the more the –NCO bond of polyisocyanate and the -OH bond of polyether polyol can fully react, while at a lower reaction temperature, Insufficient reaction between –NCO bond of polyisocyanate and –OH bond of polyether polyol will inevitably lead to low strength of prepared polyurethane foam [ 46 ]. At the beginning of the reaction, the chain expansion reaction gives off a large amount of heat, which leads to a rapid increase in the temperature of the material system.…”